化学热量计算已知下列各反应的反应热:Ca(s) + C(s,石墨) + 3/2 O2(g) = CaCO3 (s) △H = - 1206.8 kJ/molCa(s) + 1/2 O2(g) = CaO(s) △H = - 635.1 kJ/molC(s,石墨) + O2(g) = CO2 (g) △H = - 393.5 kJ/mol则CaCO3(s) = CaO(s) + CO2(g)
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![化学热量计算已知下列各反应的反应热:Ca(s) + C(s,石墨) + 3/2 O2(g) = CaCO3 (s) △H = - 1206.8 kJ/molCa(s) + 1/2 O2(g) = CaO(s) △H = - 635.1 kJ/molC(s,石墨) + O2(g) = CO2 (g) △H = - 393.5 kJ/mol则CaCO3(s) = CaO(s) + CO2(g)](/uploads/image/z/9817324-52-4.jpg?t=%E5%8C%96%E5%AD%A6%E7%83%AD%E9%87%8F%E8%AE%A1%E7%AE%97%E5%B7%B2%E7%9F%A5%E4%B8%8B%E5%88%97%E5%90%84%E5%8F%8D%E5%BA%94%E7%9A%84%E5%8F%8D%E5%BA%94%E7%83%AD%EF%BC%9ACa%28s%29+%2B+C%28s%2C%E7%9F%B3%E5%A2%A8%29+%2B+3%2F2+O2%28g%29+%3D+CaCO3+%28s%29+%E2%96%B3H+%3D+-+1206.8+kJ%2FmolCa%28s%29+%2B+1%2F2+O2%28g%29+%3D+CaO%28s%29+%E2%96%B3H+%3D+-+635.1+kJ%2FmolC%28s%2C%E7%9F%B3%E5%A2%A8%29+%2B+O2%28g%29+%3D+CO2+%28g%29+%E2%96%B3H+%3D+-+393.5+kJ%2Fmol%E5%88%99CaCO3%28s%29+%3D+CaO%28s%29+%2B+CO2%28g%29)
化学热量计算已知下列各反应的反应热:Ca(s) + C(s,石墨) + 3/2 O2(g) = CaCO3 (s) △H = - 1206.8 kJ/molCa(s) + 1/2 O2(g) = CaO(s) △H = - 635.1 kJ/molC(s,石墨) + O2(g) = CO2 (g) △H = - 393.5 kJ/mol则CaCO3(s) = CaO(s) + CO2(g)
化学热量计算
已知下列各反应的反应热:
Ca(s) + C(s,石墨) + 3/2 O2(g) = CaCO3 (s) △H = - 1206.8 kJ/mol
Ca(s) + 1/2 O2(g) = CaO(s) △H = - 635.1 kJ/mol
C(s,石墨) + O2(g) = CO2 (g) △H = - 393.5 kJ/mol
则CaCO3(s) = CaO(s) + CO2(g) 的反应热△H为
A.+178.2 kJ/mol B.-178.2 kJ/mol C.+965.3 kJ/mol D. -965.3 kJ/mol
怎么考虑?
化学热量计算已知下列各反应的反应热:Ca(s) + C(s,石墨) + 3/2 O2(g) = CaCO3 (s) △H = - 1206.8 kJ/molCa(s) + 1/2 O2(g) = CaO(s) △H = - 635.1 kJ/molC(s,石墨) + O2(g) = CO2 (g) △H = - 393.5 kJ/mol则CaCO3(s) = CaO(s) + CO2(g)
选A
CaCO3 (s) = Ca(s) + C(s,石墨) + 3/2 O2(g) △H1 = 1206.8 kJ/mol
Ca(s) + 1/2 O2(g) = CaO(s) △H2 = - 635.1 kJ/mol
C(s,石墨) + O2(g) = CO2 (g) △H3 = - 393.5 kJ/mol
以上三个反应相加,就可以得到CaCO3(s) = CaO(s) + CO2(g)
因此,反应热也是相加的关系△H =△H1+△H2+△H3=178.2 kJ/mol
A
反应2+反应3-反应1